$-\dfrac{7}{12} + \dfrac{1}{3} = {?}$
Explanation: $ = - {\dfrac{7 \times 1}{12 \times 1}} + {\dfrac{1 \times 4}{3 \times 4}} $ $ = - {\dfrac{7}{12}} + {\dfrac{4}{12}} $ $ = - \dfrac{{7} + {4}}{12} $ $ = -\dfrac{3}{12}$